Answered on February 7, 2025
Yes, regular flossing is associated with a lower risk of ischemic stroke.
Several studies have demonstrated a link between oral hygiene practices, including flossing, and a reduced risk of cardiovascular events, including ischemic stroke. For instance, a study published in the Journal of the American Dental Association found that daily flossing was associated with a lower prevalence of cardiovascular disease (CVD) events and mortality, which includes ischemic stroke, after adjusting for various confounders. The odds ratio for CVD prevalence in the daily flossing group compared to the non-flossing group was 0.71 (95% CI, 0.59 to 0.85), indicating a significant protective effect.[1]
Additionally, a study in the Journal of Periodontal Research reported that the use of floss or interdental brushes was associated with a lower risk of new cardiovascular events, including stroke, among patients with coronary heart disease. This study found a hazard ratio of 0.2 (95% CI, 0.06 to 0.6) for new cardiovascular events in patients practicing interdental cleaning compared to those who did not.[2]
Moreover, research published in Stroke has shown that regular dental care, which includes practices like flossing, is associated with a lower risk of incident ischemic stroke. Regular dental care utilization was associated with a hazard ratio of 0.77 (95% CI, 0.63 to 0.94) for stroke risk.[3]
These findings suggest that maintaining good oral hygiene, including regular flossing, may contribute to a lower risk of ischemic stroke by reducing systemic inflammation and other risk factors associated with poor oral health.

1.
The Effect of Self-Reported Flossing Behavior on Cardiovascular Disease Events and Mortality: Findings From the 2009-2016 National Health and Nutrition Examination Surveys.

Philip N, Tamimi F, Al-Sheebani A, Almuzafar A, Shi Z.

Journal of the American Dental Association (1939). 2025;156(1):17-27.e3. doi:10.1016/j.adaj.2024.09.017.

New Research

Background: There is increasing evidence suggesting that daily oral hygiene self-care measures may alleviate cardiovascular disease (CVD) risk. The authors aimed to determine the influence of self-reported dental flossing behavior on the prevalence of CVD events, CVD-linked mortality, and a CVD risk marker of inflammation (ie, C-reactive protein [CRP]).

Methods: Data from 18,801 adult participants of the 2009-2016 National Health and Nutrition Examination Surveys were analyzed with regard to flossing behavior, prevalence of CVD events, mortality cause data, and CRP levels. Information on mortality was obtained from the US mortality registry, updated to 2019. Participants who answered the flossing question were divided into 4 groups according to their frequency of flossing: not flossing (0 d/wk); occasional flossing (1-3 d/wk); frequent flossing (4-6 d/wk); and daily flossing (7 d/wk). Multiple logistic regression and Cox proportional hazard regression were used for analysis.

Results: Daily flossing was associated with lower prevalence of CVD events after adjusting for age, sex, sociodemographic factors, and lifestyle habits (model 2); the odds ratio was 0.71 (95% CI, 0.59 to 0.85) for CVD prevalence in the daily flossing group compared with the not flossing group. The odds ratio for CVD prevalence for each additional day of flossing was 0.95 (95% CI, 0.93 to 0.98; P for linear trend < .001) in model 2, and remained statistically significant after model 2 was further adjusted for metabolic syndrome. Daily flossing compared with not flossing was associated with lower risk of experiencing CVD mortality (hazard ratio, 0.64; 95% CI, 0.49 to 0.84) in model 2. The hazard ratio of CVD mortality for each additional day of flossing was 0.94 (95% CI, 0.90 to 0.98; P for linear trend = .002) in model 2. Participants in the not flossing group had significantly elevated CRP levels, even after multivariable adjustments.

Conclusions: Poor flossing behavior is associated with higher prevalence of cardiovascular events, increased risk of experiencing CVD mortality, and elevated CRP levels.

Practical Implications: Improvement in flossing behavior can have an additional benefit in the prevention of CVD events. Cardiologists need to advise patients to improve their personal oral hygiene practices, in addition to the standard diet and exercise advice.

2.
Use of Floss/­Interdental Brushes Is Associated With Lower Risk for New Cardiovascular Events Among Patients With Coronary Heart Disease.

Reichert S, Schlitt A, Beschow V, et al.

Journal of Periodontal Research. 2015;50(2):180-8. doi:10.1111/jre.12191.

Background And Objective: Periodontitis has been found to be associated with coronary heart disease (CHD) and stroke. However, only little is known about whether periodontitis and associated confounders are associated with new cardiovascular events among patients with CHD.

Material And Methods: A total of 942 inpatients with CHD were examined regarding periodontitis, oral care habits, bacteria in the subgingival biofilm and the expression of interleukin-(IL)-6 c. (coding DNA)-174 genotypes (rs 1800793) to determine whether these confounders are associated with new cardiovascular events within a 1-year follow-up period. Adjusted hazard ratios (HR) with respect of age, gender, smoking, body mass index, use of aids for interdental hygiene, plaque index, occurrence of severe periodontitis and further internal diseases such as diabetes, hypertension, dyslipoproteinemia, number of missing teeth, serological parameters and IL-6 genotypes were generated with Cox regression.

Results: In all, 941 cardiovascular patients completed the 1-year follow up and 7.3% of the patients achieved the primary endpoint (myocardial infarction: 2.1%, stroke/transient ischemic attack: 1.8%, cardiovascular deaths: 3.4%). Patients who reported practicing interdental cleaning were younger, less likely to be male or to have severe periodontitis, had a reduced tobacco exposure, had fewer missing teeth, less indices for plaque and bleeding on probing and a significant decreased adjusted risk for new cardiovascular events (HR = 0.2, CI 0.06-0.6, p = 0.01) than those patients with CHD who did not report practicing interdental cleaning. We did not obtain significant increased HR for patients with severe periodontitis (HR = 1.2, CI 0.7-2.1, p = 0.53), carriers of the IL-6 genotypes GC or CC (HR = 1.4, CI 0.8-2.5, p = 0.24) and did not find a significant association between the number of detected various oral species and the incidence of the combined endpoint (HR = 0.9, CI 0.8-1.01, p = 0.07).

Conclusions: These findings suggest that flossing and brushing of interdental spaces might reduce the risk for new cardiovascular events among patients with CHD. The hypothesis that interdental cleaning per se reduces the risk of new cardiovascular events should be examined in an interventional study.

3.
Periodontal Disease, Regular Dental Care Use, and Incident Ischemic Stroke.

Sen S, Giamberardino LD, Moss K, et al.

Stroke. 2018;49(2):355-362. doi:10.1161/STROKEAHA.117.018990.

Background And Purpose: Periodontal disease is independently associated with cardiovascular disease. Identification of periodontal disease as a risk factor for incident ischemic stroke raises the possibility that regular dental care utilization may reduce the stroke risk.

Methods: In the ARIC (Atherosclerosis Risk in Communities) study, pattern of dental visits were classified as regular or episodic dental care users. In the ancillary dental ARIC study, selected subjects from ARIC underwent fullmouth periodontal measurements collected at 6 sites per tooth and classified into 7 periodontal profile classes (PPCs).

Results: In the ARIC study 10 362 stroke-free participants, 584 participants had incident ischemic strokes over a 15-year period. In the dental ARIC study, 6736 dentate subjects were assessed for periodontal disease status using PPC with a total of 299 incident ischemic strokes over the 15-year period. The 7 levels of PPC showed a trend toward an increased stroke risk (χ trend <0.0001); the incidence rate for ischemic stroke/1000-person years was 1.29 for PPC-A (health), 2.82 for PPC-B, 4.80 for PPC-C, 3.81 for PPC-D, 3.50 for PPC-E, 4.78 for PPC-F, and 5.03 for PPC-G (severe periodontal disease). Periodontal disease was significantly associated with cardioembolic (hazard ratio, 2.6; 95% confidence interval, 1.2-5.6) and thrombotic (hazard ratio, 2.2; 95% confidence interval, 1.3-3.8) stroke subtypes. Regular dental care utilization was associated with lower adjusted stroke risk (hazard ratio, 0.77; 95% confidence interval, 0.63-0.94).

Conclusions: We confirm an independent association between periodontal disease and incident stroke risk, particularly cardioembolic and thrombotic stroke subtype. Further, we report that regular dental care utilization may lower this risk for stroke.

Expanded question: What population groups benefit most from regular flossing in terms of reducing the risk of ischemic stroke?

Answered on February 7, 2025
Younger adults and individuals with periodontal disease benefit most from regular flossing in terms of reducing the risk of ischemic stroke.
Evidence from the medical literature indicates that maintaining good oral hygiene, including regular flossing, is particularly beneficial for certain population groups. According to a study by Lee et al. in Stroke, younger adults (ages 20-44) with periodontal disease (PD) who received dental prophylaxis had a significantly lower incidence of ischemic stroke compared to those who did not receive treatment. The hazard ratio for stroke in untreated PD patients in this age group was 2.17 (95% CI, 1.64-2.87).[1]
Additionally, individuals with existing cardiovascular conditions, such as coronary heart disease (CHD), also benefit from regular interdental cleaning. Reichert et al. in the Journal of Periodontal Research found that patients with CHD who practiced interdental cleaning, including flossing, had a significantly reduced risk of new cardiovascular events, including stroke, with a hazard ratio of 0.2 (95% CI, 0.06-0.6).[2]
These findings underscore the importance of regular flossing and dental care, particularly for younger adults with periodontal disease and patients with pre-existing cardiovascular conditions, in reducing the risk of ischemic stroke.

1.
Dental Prophylaxis and Periodontal Treatment Are Protective Factors to Ischemic Stroke.

Lee YL, Hu HY, Huang N, et al.

Stroke. 2013;44(4):1026-30. doi:10.1161/STROKEAHA.111.000076.

Background And Purpose: A correlation has been found between periodontal disease (PD) and stroke. This study was conducted to investigate whether dental prophylaxis and periodontal treatment reduce the incidence rate (IR) of ischemic stroke.

Methods: We identified 510 762 PD cases and 208 674 non-PD subjects from January 1, 2000, to December 31, 2010. The PD cases were divided into dental prophylaxis, intensive treatment, and no treatment groups. The stroke IRs were assessed among groups during follow-up. Cox regression analysis was used after adjustment for age, sex, and comorbidities to determine the relationship between periodontal treatment and incidence of ischemic stroke.

Results: The stroke IR of the non-PD subjects was 0.32%/year. In the PD group, subjects who received dental prophylaxis had the lowest stroke IR (0.14%/year); subjects with intensive treatment or tooth extraction had a higher stroke IR (0.39%/year); and subjects without PD treatment had the highest stroke IR (0.48%/year; P<0.001). After adjustment for confounders, the dental prophylaxis and intensive treatment groups had a significant lower hazard ratios for stroke than the non-PD group (hazard ratio=0.78 and 0.95; 95% confidence interval=0.75-0.81 and 0.91-0.99, respectively), whereas the PD without treatment group had a significant higher hazard ratio for stroke (1.15; 95% confidence interval=1.07-1.24), especially among the youngest (20-44) age group (hazard ratio=2.17; 95% confidence interval=1.64-2.87) after stratifying for age.

Conclusions: Maintaining periodontal health by receiving dental prophylaxis and PD treatment can help reduce the incidence of ischemic stroke.

2.
Use of Floss/­Interdental Brushes Is Associated With Lower Risk for New Cardiovascular Events Among Patients With Coronary Heart Disease.

Reichert S, Schlitt A, Beschow V, et al.

Journal of Periodontal Research. 2015;50(2):180-8. doi:10.1111/jre.12191.

Background And Objective: Periodontitis has been found to be associated with coronary heart disease (CHD) and stroke. However, only little is known about whether periodontitis and associated confounders are associated with new cardiovascular events among patients with CHD.

Material And Methods: A total of 942 inpatients with CHD were examined regarding periodontitis, oral care habits, bacteria in the subgingival biofilm and the expression of interleukin-(IL)-6 c. (coding DNA)-174 genotypes (rs 1800793) to determine whether these confounders are associated with new cardiovascular events within a 1-year follow-up period. Adjusted hazard ratios (HR) with respect of age, gender, smoking, body mass index, use of aids for interdental hygiene, plaque index, occurrence of severe periodontitis and further internal diseases such as diabetes, hypertension, dyslipoproteinemia, number of missing teeth, serological parameters and IL-6 genotypes were generated with Cox regression.

Results: In all, 941 cardiovascular patients completed the 1-year follow up and 7.3% of the patients achieved the primary endpoint (myocardial infarction: 2.1%, stroke/transient ischemic attack: 1.8%, cardiovascular deaths: 3.4%). Patients who reported practicing interdental cleaning were younger, less likely to be male or to have severe periodontitis, had a reduced tobacco exposure, had fewer missing teeth, less indices for plaque and bleeding on probing and a significant decreased adjusted risk for new cardiovascular events (HR = 0.2, CI 0.06-0.6, p = 0.01) than those patients with CHD who did not report practicing interdental cleaning. We did not obtain significant increased HR for patients with severe periodontitis (HR = 1.2, CI 0.7-2.1, p = 0.53), carriers of the IL-6 genotypes GC or CC (HR = 1.4, CI 0.8-2.5, p = 0.24) and did not find a significant association between the number of detected various oral species and the incidence of the combined endpoint (HR = 0.9, CI 0.8-1.01, p = 0.07).

Conclusions: These findings suggest that flossing and brushing of interdental spaces might reduce the risk for new cardiovascular events among patients with CHD. The hypothesis that interdental cleaning per se reduces the risk of new cardiovascular events should be examined in an interventional study.